78 (number)
From Wikipedia, the free encyclopedia
78 (seventy-eight) is the natural number following 77 and followed by 79.
| Cardinal | 78 seventy-eight |
| Ordinal | 78th seventy-eighth |
| Factorization |  |
| Divisors | 1, 2, 3, 6, 13, 26, 39, 78 |
| Roman numeral | LXXVIII |
| Binary | 1001110 |
| Hexadecimal | 4E |
Contents |
[edit] In mathematics
78 is a triangular number, and its factorization makes it a sphenic number. As a multiple of perfect number, 78 is itself a semiperfect number.
77 and 78 form a Ruth-Aaron pair under the second definition in which repeated prime factors are counted as often as they occur.
Since it is possible to find sequences of 78 consecutive integers such that each inner member member shares a factor with either the first or the last member, 78 is an Erdős–Woods number.
Karl A. Dahlke proved in 1989 that 78 heptominos of this shape ( 
), at a minimum, are required to fill a rectangle.
[edit] In science
- The atomic number of platinum
- The number of chromosomes in canine DNA
A temperature which is falsely assumed to be an accurate room temperature
[edit] In astronomy
- Messier object M78, a magnitude 8.0 diffuse nebula in the constellation Orion
- The New General Catalogue object NGC 78, a magnitude 12.8 barred spiral galaxy in the constellation Pisces
- The Saros number of the solar eclipse series which began on -463 June 9 and ended on 817 July 18. The duration of Saros series 78 was 1280.1 years, and it contained 72 solar eclipses.
- The Saros number of the lunar eclipse series which began on -125 April 10 and ended on 1155 May 18. The duration of Saros series 78 was 1280.1 years, and it contained 72 lunar eclipses.
[edit] In sports
- Buffalo Bills Bruce Smith wore #78
- Cleveland Browns Ethan Kelley wears #78
- Denver Broncos Matt Lepsis wears #78
- Indianapolis Colts Tarik Glenn wears #78
- Kansas City Chiefs Bobby Bell wore #78
- Minnesota Vikings Matt Birk wears #78
- New England Patriots Bruce Armstrong wore #78
- New York Giants Walt Yowarsky wore #78
- New York Jets Garry Puetz wore #78
- Philadelphia Eagles Antone Davis wore #78
- St. Louis Rams Jackie Slater wore #78
- Bruntsfield Buffalos Jackson Thirgood wears #78
[edit] In other fields
78 is also:
- In reference to gramophone records, 78 refers those meant to be spun at 78 revolutions per minute. Compare: LP, 33 1/3 and 45 rpm.
- A standard Tarot deck containing the 21 trump cards, the fool and the 56 suit cards make up 78 cards.
- The number of the French département Yvelines
- The total number of gifts in the song The Twelve Days of Christmas (since 78 is the 12th triangular number).
- The year AD 78, 78 BC, or 1978.
- The number of lines that make up Metatron's Cube.
- Many numbered highways in the United States
